Object of the present invention is a female contact, adapted to receive a male contact of the pin type in which when the pin is not inserted the areas intended to establish the electric contact with the pin, upon insertion of same, are arranged at least approximately according to a family of straight generatrices of a hyperboloid of revolution of one branch.
A contact of such type is known for example from U.S. Pat. No. 4,447,108 in the name of the same inventor: said contact is constructed in a single piece, made of any suitable conductive metal or metal alloy, for example a brass alloy used in components for electric conduction. Said type of contact, although satisfactory, can in some cases present some disadvantages, and precisely:
In the case that, following to particular standard rules or functional requirements, the contact must bear, while maintaining unaltered its characteristic features of elasticity and electric conductivity, high temperatures and repeated mechanical stresses (depending upon the insertion and removal performed a plurality of times of the male pin contact), it is desirable to construct the said contact by using particular metals or metal alloys (such as for example a copper-beryllium alloy). In such a case however there arises the problem relating to the parts of the contact which are not intended to receive the pin contact, such as for example the appendices for the connection with the electric circuits, for which it is required that there be maintained the features of plastic deformability proper to brass or similar alloys and which instead are not possessed by harder metals or alloys (such as for example the above indicated copper-beryllium alloy);
In the more general case in which due to particular requirements of electric conductivity, chemical or thermic resistance, the portion contacting the pin contact must be made of expensive metals or metal alloys, it is evident that the construction of the whole contact in said metal or metal alloy leads necessarily to a remarkable increase of the cost of the contact itself.
In order to avoid such inconveniences, the invention contemplates a female contact of the above described type, characterized by the fact of being composite, i.e. of comprising:
a proper elastic contact element (intended to receive the pin contact) consisting of a cylindrical sleeve made of any suitable metal or metal alloy, provided with through slots arranged on its cylindrical surface and inclined with respect to the longitudinal axis of said sleeve, said sleeve being subjected to permanent deformation by twisting according to a predetermined angle and directed in the sense of inclination of the slots;
a housing body, made of any suitable metal or metal alloy, and presenting a cavity apt to house in a stable manner the said elastic contact element, for its electric connection with any type of circuit.
According to a characteristic feature of the invention the sleeve, which constitutes the elastic element of the contact, is made of the metal or metal alloy which is required for its features of unaltered elasticity and electric conductivity also in presence of high changes of temperatures and repeated mechanical stresses, while the housing body is made of metal or metal alloy of the type normally used in components for electric conduction.